The present invention relates to a laser printing method and a laser printing apparatus and, more particularly, relates to laser printing method and apparatus suitable for printing characters on base material such as glassy or vitreous material by using laser light beam.
In a module used for a conventional general purpose computer or the like, a carrier board (MMC: microchip for carrier) on which an LSI (large scale integrated circuit) or the like is attached is mounted on a multi layer wiring circuit board (MLC: multi layer ceramics). Number or the like such as a serial number is usually printed on the side surface of the MCC board so as to perform the management of the production or the like. Conventionally, mullite/W has been employed as the material of the MCC board. Further, a YAG laser has been employed as a laser oscillator in the conventional laser printing apparatus for printing characters on the mullite/W board.
Recently, a module used in a general purpose computer has been highly integrated as an LSI, and the MCC has been required to have high accuracy in its parts in accordance with the progress of the integration. The accuracy of the, parts is required in the warp of the board, variance in the plate thickness of the board, pitch or the like. The inventors of the present application consider to employ glass/Cu in place of the conventional mullite/W as the material of the board having such a high parts accuracy. It was proved that the parts accuracy can be improved by using the glass/Cu. However, on the other hand, it was proved that the printing quality is not good when the conventional laser printing apparatus prints characters on the glass material such as glass/Cu. To be more concrete, when small-sized characters each having such a width of 0.47 mm and a height of 0.7 mm are printed, it was impossible to discriminate such characters.
Accordingly, an object of the present invention is to provide a laser printing method and a laser printing apparatus which can improve printing quality.
In order to attain the aforesaid object, the present invention is arranged in a manner that in a laser printing method for printing on a member to be printed by using laser light emitted from a laser oscillator, the printing is performed on the member to be printed by using laser light emitted from a solid-state laser oscillator serving as the laser oscillator which emits laser light of third harmonics in an ultraviolet range.
Further, the present invention is arranged in a manner that the laser printing apparatus comprises a laser oscillator, a scanning means for scanning laser light emitted from the laser oscillator, and a converging means for converging the laser light emitted from the laser oscillator on a member to be printed and prints on the member to be printed by using laser light emitted from the laser oscillator, wherein the laser oscillator is a solidstate laser oscillator which emits laser light of third harmonics in an ultraviolet range.
According to such a configuration of the present invention, clear printing can be performed also on a glass type board or the like and the printing quality can be improved.